[Libav-user] Redirecting MP4 muxed data to socket using movflags resets timestamp
Parth V Shah
parth.vshah at einfochips.com
Mon Sep 1 10:43:18 CEST 2014
I am using FFMPEG library to mux H.264 and AAC frames to MP4 file. I do that C program.
I store H.264 and AAC frame's timestamp in epoch format.
I use ffprobe to check timestamps that stored in the MP4 file, ffprobe confirms that file is in MP4 format and timestamps are stored correctly. below is the output of ffprobe.
* ffprobe -show_packets 20140805095931.mp4
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '20140805095931.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf54.29.104
Duration: 00:01:39.70, start: 1407232771.984000, bitrate: 1063 kb/s
Stream #0.0(und): Video: h264 (High), yuv420p, 960x540, 999 kb/s, 30 fps, 59.94 tbr, 1k tbn, 60 tbc
Stream #0.1(und): Audio: aac, 48000 Hz, mono, s16, 53 kb/s
[PACKET]
codec_type=video
stream_index=0
pts=1407232771984
pts_time=1407232771.984000
dts=1407232771984
dts_time=1407232771.984000
duration=34
duration_time=0.034000
size=24556.000000
pos=48
flags=K
[/PACKET]
[PACKET]
codec_type=video
stream_index=0
pts=1407232772018
pts_time=1407232772.018000
dts=1407232772018
dts_time=1407232772.018000
duration=33
duration_time=0.033000
size=3180.000000
pos=24604
flags=_
[/PACKET]
[PACKET]
codec_type=video
stream_index=0
pts=1407232772051
pts_time=1407232772.051000
dts=1407232772051
dts_time=1407232772.051000
duration=33
duration_time=0.033000
size=3209.000000
pos=27784
flags=_
[/PACKET]
My goal is reading this muxed MP4 data from MP4 file and send this muxed mp4 data to the client over socket without creating any temporary file. My actual goal is to write a C program though.
I tried using protocols tcp and udp but they are not working with Mp4 format and gives error as below.
ffmpeg -i 20140805095931.mp4 -f mp4 -vcodec copy tcp://10.99.19.163:8888
[mp4 @ 0xb1e1920] muxer does not support non seekable output
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
So, I read somewhere about moov atom and tried it with following command
ffmpeg -i 20140805095931.mp4 -movflags isml+frag_keyframe -f mp4 -vcodec copy tcp://10.99.19.163:8888
using above commandline I am able to send mp4 file to the client using tcp protocol that ffmpeg supports.
But when I apply ffprobe on the MP4 file timestamp resets to 0 , even starttime becomes 0.0000. Below is the output of ffmpeg.
* ffprobe -show_packets out.mp4
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf55.48.100
Duration: 00:01:39.71, start: 0.000000, bitrate: 1059 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 960x540, 999 kb/s, 30 fps, 30 tbr, 16k tbn, 60 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 48000 Hz, mono, fltp, 53 kb/s (default)
Metadata:
handler_name : SoundHandler
[PACKET]
codec_type=video
stream_index=0
pts=0
pts_time=0.000000
dts=0
dts_time=0.000000
duration=533
duration_time=0.033313
convergence_duration=N/A
convergence_duration_time=N/A
size=24556
pos=3853
flags=K
[/PACKET]
[PACKET]
codec_type=video
stream_index=0
pts=544
pts_time=0.034000
dts=544
dts_time=0.034000
duration=533
duration_time=0.033313
convergence_duration=N/A
convergence_duration_time=N/A
size=3180
pos=28409
flags=_
[/PACKET]
[PACKET]
codec_type=video
stream_index=0
pts=1072
pts_time=0.067000
dts=1072
dts_time=0.067000
duration=533
duration_time=0.033313
convergence_duration=N/A
convergence_duration_time=N/A
size=3209
pos=31589
flags=_
[/PACKET]
Any help or advice? Thank you in advance. ************************************************************************************************************************************************************* eInfochips Business Disclaimer: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer. Any views expressed in this message are those of the individual sender unless otherwise stated. Company has taken enough precautions to prevent the spread of viruses. However the company accepts no liability for any damage caused by any virus transmitted by this email. *************************************************************************************************************************************************************
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